Multi-Electrode Optical DAC Modulator for Wider Dynamic Range
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Solution Overview
Problem
Current digital-to-analog converters, particularly those using Mach-Zehnder Interferometer modulators, face challenges with non-linearity, limiting their dynamic range and resolution in analog signal conversion, which is critical for high-bandwidth applications like wireless communication and medical imaging.
Innovation Solution
A linearized optical digital-to-analog modulator is developed, utilizing an electrically controllable modulator with multiple actuating electrodes and an electrode actuating device that applies voltages based on multiple bits of the input data word, employing a digital-to-digital converter to optimize electrode actuation patterns and lengths for improved linearity and dynamic range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a Mach-Zehnder Interferometer modulator is used for digital-to-analog conversion, then the device can achieve high-speed modulation and long-haul transmission capability, but the inherent non-linear response limits dynamic range and resolution
Solution Approach 1:
The modulator is divided into multiple independently controllable sections, each with its own electrode. By segmenting the single nonlinear modulator into multiple sections, the patent enables independent control of each segment's contribution to the overall output, allowing digital-to-analog conversion with improved linearity while maintaining high-speed modulation capabilities
Solution Approach 2:
The patent changes the operational parameters by applying different voltages to multiple modulator sections based on the input digital word. By varying the voltage parameters across multiple sections rather than using a single voltage control, the system achieves linearized output response while preserving the high-speed modulation characteristic of the Mach-Zehnder Interferometer
2Measurement precision
If the modulation range is reduced to operate in a quasi-linear regime, then linearity improves, but the dynamic range and bandwidth are limited
Solution Approach 1:
By segmenting the modulator into multiple sections that can be independently controlled, the patent allows the system to operate in a quasi-linear regime for each individual section while combining their outputs to achieve a much larger overall dynamic range. This segmentation enables both high linearity and extended bandwidth simultaneously
Solution Approach 2:
The patent merges the outputs of multiple modulator sections, each operating in a linear regime with limited individual dynamic range. By combining these segmented outputs constructively, the system achieves a cumulative dynamic range that exceeds what any single section could provide, while maintaining the linearity benefits of operating in the quasi-linear regime
3Measurement precision
If multiple electrodes with different sectioning lengths are used, then dynamic range and resolution improve, but the device complexity increases
Solution Approach 1:
The patent segments the modulator into multiple sections with different electrode lengths, where each section contributes differently to the overall output. This segmentation enables fine-grained control over the analog output level, achieving high dynamic range and resolution. The complexity is managed by using a systematic approach to segmenting rather than arbitrary complex configurations
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves enhanced linearity and dynamic range in digital-to-analog conversion, effectively addressing the non-linearity issues of existing modulators, enabling higher performance in multi-GHz mixed-signal systems and supporting increased bandwidth demands.
Implementation Method 1
since the modulating voltage via the electro-optic effect controls the optical phase delay in a basically linear fashion
Data Source
AI summary
A system for converting digital data into a modulated optical signal, comprises an electrically controllable device having M actuating electrodes. The device provides an optical signal that is modulated in response to binary voltages applied to the actuating electrodes. The system also comprises a digital-to-digital converter that provides a mapping of input data words to binary actuation vectors of M bits and supplies the binary actuation vectors as M bits of binary actuation voltages to the M actuating electrodes, where M is larger than the number of bits in each input data word. The digital-to-digital converter is enabled to map each digital input data word to a binary actuation vector by selecting a binary actuation vector from a subset of binary actuation vectors available to represent each of the input data words.